Ingredient info: Fresh porcini mushrooms are available in the fall and spring at some farmers' markets and online from oregonmushrooms.com. If you're at the market, ask the purveyor to cut the mushrooms in half so that you can look at the stem. It should be white, without any tiny holes.

Meanwhile, cook green beans in large
pot of boiling salted water until crisptender,
4 to 5 minutes. Drain green beans
and spread out on another rimmed baking
sheet to cool. Heat 1 1/2 tablespoons reserved
duck fat in heavy large skillet over medium high
heat. Add 1/3 of mushrooms; sprinkle
with salt and pepper. Sauté mushrooms
until tender and beginning to brown, 2
to 3 minutes. Transfer to bowl. Working
in 2 more batches, repeat with duck fat,
remaining mushrooms, and salt and pepper.

Transfer duck to plate; let rest. Add
mushrooms to green beans on baking
sheet; toss. Roast until heated through,
about 15 minutes. Season to taste with salt
and pepper. Using tongs, tilt duck to drain
juices from cavity onto plate.

Place duck on platter; pour juices
from plate onto rimmed baking sheet with
vegetables. Using slotted spoon, transfer
vegetables to platter; arrange around duck.
Pour off pan juices from baking sheet into
medium bowl. Spoon off fat from surface;
discard fat and reserve juices. Place baking
sheet over 2 burners on stovetop. Add
reserved juices and broth to baking sheet.
Bring to boil, scraping up any browned bits.
Pour pan juices into small pitcher; season
with salt and pepper.